Fax And Modem Capabilities; Fax/Modem Operating Modes; Fax/Modem Transport Modes - AudioCodes Mediant 2000 User Manual

9.5

Fax and Modem Capabilities

This section describes the device's fax and modem capabilities, and includes the following
main subsections:

Fax and modem operating modes (refer to ''Fax/Modem Operating Modes''
410 )

Fax and modem transport modes (refer to ''Fax/Modem Transport Modes''
410 )

V.34 fax support (refer to ''V.34 Fax Support''

V.152 support (refer to ''V.152 Support''
9.5.1

Fax/Modem Operating Modes

The device supports two modes of operations:

Fax/modem negotiation that is not performed during the establishment of the call.

Voice-band data (VBD) mode for V.152 implementation (refer to ''V.152 Support''
page 417
endpoint at the establishment of the call. During a call, when a fax/modem signal is
detected, transition from voice to VBD (or T.38) is automatically performed and no
additional SIP signaling is required. If negotiation fails (i.e., no match is achieved for
any of the transport capabilities), fallback to existing logic occurs (according to the
parameter IsFaxUsed).
9.5.2

Fax/Modem Transport Modes

The device supports the following transport modes for fax per modem type
(V.22/V.23/Bell/V.32/V.34):

T.38 fax relay (refer to ''Fax Relay Mode''

Fax and modem bypass: a proprietary method that uses a high bit rate coder (refer to
''Fax/Modem Bypass Mode''

NSE Cisco's Pass-through bypass mode for fax and modem (refer to ''Fax / Modem
NSE Mode''

Transparent: passing the fax / modem signal in the current voice coder (refer to ''Fax /
Modem Transparent Mode''

Transparent with events: passing the fax / modem signal in the current voice coder
with adaptations (refer to ''Fax / Modem Transparent with Events Mode''

G.711 Transport: switching to G.711 when fax/modem is detected (refer to ''G.711 Fax
/ Modem Transport Mode''

Fax fallback to G.711 if T.38 is not supported (refer to ''Fax Fallback''
'Adaptations' refer to automatic reconfiguration of certain DSP features for handling
fax/modem streams differently than voice.
SIP User's Manual
): fax/modem capabilities are negotiated between the device and the remote
on page
on page 413 )
on page
on page
on page 416
on page 417 )
on page 411 )
412 )
414 )
415 )
410
Mediant 2000
on page
on page
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on
on page 414
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Document #: LTRT-68809
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